Some people were asking how/why this works, and skimming over the thread I didn't see a thorough explanation, so I'm going to take a stab at it. I may be wrong, but I think I understand what's happening physics-wise.

Think of a pogo stick...sideways. When you toss the car into a drift, the body rolls over to one side. (the opposite side from the direction you are turning) Now the springs on that side have compressed, and will "bounce" back up, sending that energy/movement across the car to the other side, causing it to lose a little grip on the tires that need it, and causing the car to sort of jump sideways in the wrong direction. Now the cycle repeats and you're fishtailing.

By restricting the rebound of that "pogo stick" spring, the car stays squatted down on that first side a little longer, and more gradually rises, which tends to upset the balance LESS and sends that transfer of energy/movement back across the car more gradually, giving you time to react and adjust the steering angle.

Thicker oil will have somewhat the same effect, but it can also slow down the compression so much that the tires can't follow the contour of the ground properly, and you end up with a car that spends more time out of contact with the surface than not.

One thing you should be aware of when increasing the rebound stiffness like this, is that you can go too far and cause the shocks to "jack down" and get fully compressed in a turn with bumps before they get a chance to rebound enough to function. When this happens the shocks hit their stops and stop working until they get a moment to release some of that compression. During that time you will likely see a dramatic loss of traction as the tire slams and bounces across the surface.

So I hope that helps with understanding why this works. It's a great mod that I've been doing with all kinds of RC cars for 10-15 years...works great on off-road stuff too!

Dude, serious work !!!F-1 genius engineering. About the plate holes guys, a different number of them will cause a different result, obvious, so it's just need to try out to find what combination fits better your chassis/shocks.Thank you very much, hamster82 !!!best regards!

Hello EverybodyI must be missing a step! I am trying to mod my yokomo shocks and it just is not working. I have tried light oil and heavy oil- and different types of plastic for the shims and I do not get the same effect- I live in Japan and No one around here has heard of this mod so I figure I would be the first to do it. As of now I am just wasting shock oil and cutting holes in paper protectors and even a plastic bag- is there something qwerky with the yokomo shock kit- there is plenty of play between the shock wall and the inner three hole ?shim?